Field of the Invention
The present invention relates to a yellow toner to be used in a recording method such as an electrophotographic method, an electrostatic recording method, a magnetic recording method, or a toner jet method, and to a production method therefor.
Description of the Related Art
In recent years, there has been an increasing demand for an improvement in image quality along with increasing popularity of a color image. In a digital full color copying machine or printer, a color original image is subjected to color separation with filters for blue, green, and red colors, and latent images corresponding to the original image are then developed with developers for yellow, magenta, cyan, and black colors. Therefore, coloring power of colorant in the developer for each color has a large influence on image quality.
It is important to reproduce Japan Color in the printing industry or approximate Adobe RGB used in an RGB workflow. In order to secure such color space, it is effective to use a dyestuff having a wide color gamut.
As typical examples of a yellow colorant for toner, there are known compounds each having, for example, an isoindolinone, quinophthalone, isoindoline, anthraquinone, or azo skeleton. Of those, as a yellow dyestuff, there are known some examples each using a pyridone azo skeleton such as C.I. Solvent Yellow 162, which has high transparency and coloring power and is excellent in light fastness (see Japanese Patent Application Laid-Open No. H07-140716 and Japanese Patent Application Laid-Open No. H11-282208).
In addition, a pyridone azo compound having a phenyl group that is disubstituted or more highly substituted is known to be used for a color filter (see International Publication No. WO2012/039361).